An ultimatum is the death sentence of a relationship.

Assuming you are in a relationship with someone of shared values, ultimatums become unnecessary however if ultimatums are proffered it is often because someone was dishonest at some point in a major way.  Resolve to never use ultimatums by doing the hard work ahead of time to explore your partners values and see if they align with yours, if they don’t, these is nothing you can change, the only thing that can happen is for you to live with their differing point of view.  The problem is, life has a way of showing us who we are over time and if your partner has different values then you, it will cause a major issue down the road. This is often where an ultimatum comes from and once expressed, is likely the beginning of the end.